Fluid-pressure-operated hammer



2. Shees-Sheet l July 5,1927..

f l E. w. STEVENS FLUID PRESSURE OPERATED Hman l Filed Nov.'11. 1s2o.Hill

nl... .uni n I \N um@ N mw Q. was WN mv m Q@ M Jul 5 192 634 729 r y 7E. w. STEVENS .1..

V FLUID PRESSURE OPERATED HAMMER i Filed N v.11. 1920 2 sheets-snm zIHHIIIIIIII "mimi" Patented July 5, 1927.

y 1.634329 UNiTED STATES PATE-ur ortica.

EDWARD W. STEVENS, OF DETROIT, MICHIGAN. ASSIGNOR TC CHICAGO NEUMATICTOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEV JERSEY.

rLUm-PREssoRE-OPERATED HAMMER.

Application filed November 11, 1920. Serial No. 423,264.

My invention relates to fluid pressure operated hammers and the objectthereof is to produce a simple and efficient hammer of this type usedmore particularly but not necessarily, as a sand rannner andcharacterized by a novel economical construction of parts and a newinode of operation, particularly as to the valve. Various features ofadvantage and utility in my new hammer.

will be apparent from the desciption hereinafter given.

\ 1n the drawings Fig. v1 is a central longitudinal section of. a hammerembodying my invention; Fig. 2 a fragmentary sectional viewsubstantially von the line 2-2 of Fig. 1; Fig. 3, an enlarged view ofthe rear portion of the hammer of Fig. A1; Fig. 4 an elevation of oneend of the Valve block; Fig. 5 a section of such block on the line 5 5of Fig. 6; Fig. 6 an elevation of the other end of the block; Fig. 7 asection on the line 7 7 of Fig. 4.; Figs. 8 and 9 sections on thecorrespondingly indicated section lines respectively of Fig. 6; Fig.

l0 a detail view of the valve alone; Fig.

11; Fig, 13 an elevation of the rear end of the cylinder; Fig. 14: anelevation of the rear end head or socket of the hammer.

Referring to the present embodiment of my invention as herein shown,-thehammer comprises a cylinder or barrel 1, having a piston chamber 2v inwhich the piston 3 reciprocates7 a valve blockl or box 4 located at therear end of the cylinder and prefer-r ably provided witha separate lidor cover 5, a valve 6 reciprocable in the block and a head or socket 7,within which the valve and block are located and which engages the rearend of the cylinder for clamping the block in place at the rear end ofsuch cylinder. Y

Referring in detail to the valve mechanism, the block is substantiallytruncated conical being provided with a valve chamber S and with threeinterior circumferential grooves 9, 10 and 11. rlhe rear end of thisvalve chamber communicates constantly with the source of motive fluidadmitted through the rear end of the head 7 by the pipe connection 12.By reason of the peculiar formation of the exterior of the block, thereis formed between it and the interior of the wall of the head 7 anexhaust Vsupply through the narrow space 23u.

chamber 13.' The groove 9 is provided with one or more relief ports 14communi'- cating with the exhaust chamber 13 so as to permit of freemovement of the valve'. The groove 10 comnniuicates with passages 15which are here two in number and which extend through the .lid 5 andthrough the the walls of the cylinder to the forward end of the pistonchamber where they `emerge thereinto as ports 16. The groove 11communicates with ports 17 which are here two 'in number and which passthrough the lid 5 and part way down the walls' of the cylinder untilthey emerge into the rear end of the piston chamber through the ports18.

The valve block is also. provided with a series of passages 19 which arehere four in -number and which pass through the larger diameter portionof the block and communicate freely with the exhaust chamber 13. Thesepassages 19 also'pass through the lid 5 and extend forwardly ordownwardly through the walls of the cylinder and emerge at their forwardends through i the ports 2O into the interior of the cylinder.

These passages 19 also communicate with the piston chamber at the twopoints 21 and 22 located at different distances from the rear end ofthecylinder.

The valve block is also provided with an inclined passage23 extendingfrom end to end thereof and communicating at its rear ward endconstantly with the motive fluid This passage 23 extends through Vthelid 5 and communicates with a passalge 241 in such lid which latterpassage communicates at' its inner end with the forward end of the valvechamber. These passages 23 and 241 thus form a by-pass between oppositeends or pressure areas of the valve. This passage 23 also communicatesthrough the passage25 with the piston chamber through a port 26 locatedat a predetermined distance from the rear end of the piston chamber.

The valveti is substantially a hollow cylinder closed at one end andprovided with ports and grooves for the supply and exhaust of the motivefluid to and from the piston chamber. As shown, the valve ,is providedwith a series of radial ports 2T communicating with the hollow interior28 of the valve which is constantly supplied with the motive fiuid. Thevalve is also provided with the circumferential groove 29 adapted tospan. the groove 10 and radial ports 30 in the. block, which portscommunicate with one of the passages 19, also with the exhaust chamber13. The valve is further provided with a series of radial ports 31,adapted to communicate with the passages 17 for supplying the rear endof the piston chamber with the motive fluid.

Describing a cycle ofoperation Iand starting with the valve andpistoniii-.the pos:- tion shown in Figs--1 and 2, the valve has already'beenshifted rearwai-dlyr and is now admitting-the motive fluid from `pipe 12to the rear endlofthepiston. chamber through thebore'offfthevalve ports31, groove 11, passages 17 and ports 18: The piston is nowready--tomove-forwardly and to deliver itsblowthrough its shank erstem 32 whichmaybe the worlctool-:itself'or to whichy a tool may bevattached. Atithis time also the forwardiendofthe piston chamber is at exhaust throughthe ports and 1 passages 16 and 15, groove 29, port 30, exhaust chamber13 and ffl-nal iexhaustiport. The valve is held in' this rearward:position by the motivel fluid admitted ithrough the byepass passages23wandi24l to the :forward or larger` pressure area of the valve whichoperates in the forward end of thevalvechamber. 'ilvhen the piston hasmoved forwardly. so as to` wheny 1 the, piston on) its f forwardmovement uncovers the, por=t121, the pressure. ini the rear end of thepiston l chamber will be lnitially'eiihausted orireduced to such anexeltentthat the pressure intheforward end of the valve chamberhwill;berelieved :to-such :in-extent belcivithe line-pressure thatthe motivefluid acting on the lesser or rearward press-ure areaot'the valve willshiftsuch. 'valve forwardly. At this. time the. rear end ofthe piston`chfnnber is placed atieX- haust through. the ports and passages 18andi1T, grooves'll and .'297 port 30,.chamber; 13 Aand exhaust .portslslorthe forward;

end fof 'the piston chamber 4*is supplied with motive fluid through theports 2?, groove, 10,v Dassages 15, and Sport 16, with the result thatthe pistonA ismoved rearwardlyand as soon as it covers 26:the1exhaust.of the bypassed-` notivev fluidy through passage 25 ceases andpressurebuilds up behind the val-ve causing it to shift'` rearwardly and thuscompletingthe. cycle. The forwardend of the piston. chamber isiexhausted not only through the port 16 but also through the ports 21 and22, untilsuch time as; the piston in its forward movement covers thelatter. The relief ports 14 prevent any m0- tive -Huid b'eing trappedlso as to interfere ofithe ports 19 extends asa port-2OI for the purposeIof: supplying I air through.

the passage, 3fjformed in fthe forward gland 35il throughthe space38-and thence-.out-4 wardly through the annular passage` 36l around.,the shank. 32, thereby supplyingithe motiverfltnd to the `forward endof thetool for :the ,usual purposes.

Firom :the abofveeit will be lapparentthat the disposition andarrangementbf thebypass passages V23 and 2ilrelativeuto passage25vleading'fto thetpistonf chamber are such that f a ,suction effect ,Iis produced in the forward endl of the, valvei chamber when the.-

rear of the pistongchamber is ,open toweX'-, haust, that theYpassagesl;y in effect-comprise -anegector 3 2stl and 25, then,

for,the forward end ofithevalve chambeiethat; the control ofthe.outletport.h 26 Aofipassagex `25 by the pistons determines whetlrier,the vli've motive fl-uid continuously supplied bycpassage L23 shallbuild up pressureinl the .forward ,vend of the valve Vchamber tol shiftAthe valve rearwardlyorishall produce a suction,;effectV to lassistinfthe forward movement` ofthe valve, land nthat the -.contin,uation.,oftheisuction ieffectqthrough ther-action of the ejector providedbynpassages 23, 24,;and. .25 remains effectivet to .hold the valve aagainst rebound ein fluttering directly, after the valve g has shiftedforwardly.,

l claim: Y

1. A; fluid; pressure operatedl hammer comprising a; cylinder havingpistonA chamber, l a! piston: reciprocablejtherein, a

valve. bloclnhaving a valvey chamber and4 closingthe,y rear eno yof the1piston chamber, a=valve-rec1procable iin the valve, chamber and. havingva pressure area constantlyi eX.-V

posed.: ltotheamotive fluid supply and having aflarger,pressureareaexposedA to variable:

pressure, said hamm-er having a constantly4 open .by-pass` between; saidlsupply and :said larger. pressure` areaaanda passage; from said by-passV,to thecrear'end ofltherpiston. cliambeiggsaid passagebeing controlledbyl the piston in its reciprocations, c

2. Ai fluid, pressure operated hammer.`

comprising a cylinder having al` piston. chairfoer,V agpistonreciprocable: therein, a.

valve blocky havingavalve chamber and closingithe rear, end oflthepistonchamber,

a valve,reciprocable in the valve ,chamber andv havingE a pressurearea., constantlyexposed to the motive fluid supply and having a largerpressure area exposed to variable pressure, said valve being inalignment with the piston chamber and shiftable forvvardly by suchconstant motive fluid pressure, said hammer having a constantly op-enby-pass extending from said supply and aroundthe valve to the front endof the valve chamber, and also having a passage extending from thepiston chamber through a port located at a predetermined point from itsrear end to said by-pass and thereby also communieating` with the frontend oi' the valve chamber, said port beingl controlled by the piston inits reciprocations.

3. A fluid pressure operated hammer comprising a cylinder having a,piston chamber, :i piston .reciprocable therein, a valve block having avalve chamber and having a removable lid arranged at the rear of thecylinder and closing the piston chamber, a valve reciprocahle in thevalve chainber and having at its outer end a pressure area constantlyexposed to the motive fluid supply and a larger pressure area at itsother end exposed to variable pressure, said block and lid having aily-pass maintaining` constant communication between the two pressureareas and the cylinder having` a passage between the rear tou chamberand thel by-pass, said passage being controlled by the piston to controlthe shifting of the valve.

el. A fluid pressure operated hammer comprising a cylinder having apiston chamber, piston reeiprocable therein, a valve block having avalve chamber and having a removable lid arranged at the rear of thecylinder and closing the piston chamber, a valve reciprocable in thevalve chamber and having at its outer end a pressure area constantlyexposed to th-e motive fluid supply and a larger pressure area at itsother end exposed to variable pressure, said block and lid having a bv-pass maintaining constant conin'uinication between the two pressureareas and the cylinder having a passage between the rear portion of thepiston chamber and the by-pass, ,said piston chamber having` an exhaustport in rearward portion and in advance of said passage and controlledby the piston to relieve the pressure against the larger pressure areaof the valve.

5. A fluid pressure operated hammer comprising a cylinder having apiston chamber, a piston reciprocable therein` a valve block having avalve chamber and closing the rear end of the piston chamber, a valvereciprocable in the valve chamber and having a pressure area constantlyexposed to the motive Huid supply for moving the valve in one directionand a larger pressure area for moving it in the opposite direction, saidvalve being in alignment with the piston chamber and being in the formof a hollow portion of the pisi cylinder closed at one end and havingports and grooves for controlling the admission andrexhaust of pressureto opposite sides of he piston, said hammer having a by-pass eX-tendi-ng to said larger valve area, said bypasshaving a constantly openmotive fluid inlet of restricted size and a connection to the pistonchamber under control of said piston, said connection being so arrangedyrelative to said by-pass as to make the niohaving a pressureareaconstantly exposed to the motive fluid supply for moving the valve inone direction and a larger pressure area for moving it in the oppositedirection, said valve being in alignmentkvvith the piston chamber andbeing shiftable forward by such 'constant motive fluid pressure, saidvalve being a hollow cylinder closed at one end and having ports andgrooves for con-- trolling the admission and exhaust of presy sure toopposite sides of thev piston, said block and lid having Vpassagesuncontrolled by said valve comprising a by-pass extending'to said largervalve area, the block passage of said by-pass having a constantly openmotive fluid inlet of restricted size, and a passage substantially indirect line with said block passage communicating with the pistonchamber and controlled by said piston thereby to effect a building up ofpressure against said larger area to shift the valve When said lastnamed passage is closed by said piston, the lid passage of said by-passbeing at an acute angle to said block passage thereby to produce asuction effect on said larger valve area and assist the smaller constantpressure area of the valve quickly to shift the same when the pistoncontrolled passage is opened to exhaust.

7. A pneumatic hammer having in combination a cylinder,` a hammerpiston, a valve for controlling said hammer piston, said valve having aWorking pressure surface, and means including fluid conduits controlledby said hammer piston for alternately subjecting said Working pressuresurface topositive fluid pressure and to suction.

8. A pneumatic hammer having in combination a cylinder, a hammer piston,a valve for controlling said hammer piston, said valve having a Workingpressure surface, and means including fluid conduits for altei-natelysubjecting said Working pressure rso 2e valve\ having a Workin@` surfaceto positive fluid pressure4 'and to Ssuction' 9i AS- pneum'atic hammerhaving'inlcombination avplurality of movable members `r oneoitWhich'serves as a hainn'ierpiston' and another as al valvev said valvecontrolling said hammer piston and having a'pressure surface', andmeansinclud-ing fluid 1conduits controlled'fby theunovementof one o'i-saidi0L members or" alternately subjecting said;

pressure"surfaceto positive pressure and tol suction'.

10. Ai pneumatic hammer having in eom' bination al cylinder, a hammer, avalve,

` means providi-ng'an ejectorl having* adischargeh conduit;commun'icating` f With the at# mosphere by Way'- offthe hammer cham-loerof* said lcylinder, means -or intermittently interruptingsuchf'comnninicatieii, a-n'd saidi b pressure surfaceacted uponbygaseous lfuidthe' degreel of pressureA oitl1 whichv is controlled bysaidi ejector.

ll! A* pneumatic hammer having inl Icoin-- lfbination a cylinder,v ahan'nner, a valve,A

means providing an ejector cooperating' vvitlr saldvalve, and means foralternatelyl open-l lng` and closing the discharge conduitf of said'ejector 12".' A pneumatic hammerfhavingin com-l bin'ation a cylinder,ahammer, a valve1liaving a Working pressure surface,` means pro'-vidingan ejectordischarging 'into said cyl" vinder and arranged`frcreatlng suction onsaid Working pressure surface, an eXhaust passagey'for said cylinder controlled 'by said' valve, and 'said hammercontrolling` the discharge of said ejector into said 'cylinder'.

13.. pneumatic hammer havin'gin comandai :Working pressure .surface otdifferent area lelilective to move the valve in an oppositedi-rection,means ior admitting motive liu-id'to saidfirstsui-ace, means providinglani ejector for creating suction -on` said secondmentioned'area, andmeans for interruptiiigthe*k discharge from' said ejector for arising'thebu'ilding up oi pressure on said second mentioned area.

l5. pneumatic hammer having in `com'- bin'ation` cylinder, a hammerandcon trolling valve, said valve havingl a Yforwardlyvactingworliingfpressure surface and a rearwardly acting Workingypressure surface, andmeans for suhjectingone'o'f said surfaces topressure fluid at'high pressure fori slntingsaid 'valveand theI other tosuction foulocliing said lvalve when' shifted and for subjecting thelatter pressure surface to positive pressure for overcoming the pressureont'ne lirst acting surface' 4[orJ ai,.in shitting said valve. y

EUX/JARD WV'. STEVENS.

